Water Pollution: Understanding Its Human Causes

Water pollution is the contamination of water bodies, including lakes, rivers, oceans, and groundwater, which has a detrimental impact on their uses. It is predominantly caused by human activities, including industrial, agricultural, and residential waste, as well as particles, noise, excess carbon dioxide, and invasive species. Water pollution can also be caused by oil spills, leaks from pipelines, and the use of water as a coolant by power plants and manufacturers. Additionally, stormwater runoff, untreated sewage, and wind contribute to water pollution by carrying debris, such as plastic waste, into waterways. Climate change exacerbates water pollution, with extreme weather conditions worsening water quality and warmer temperatures facilitating the growth of harmful algal blooms.

Industrial waste

Water pollution is caused by industrial waste in several ways. Firstly, industrial activities generate large amounts of wastewater, which can be contaminated with toxic substances. This wastewater is often discharged directly into nearby public waters, such as rivers, lakes, and seas, without proper treatment. The quality and quantity of wastewater generated depend on the type of industry. For example, it can contain non-biodegradable waste such as heavy metals, pesticides, plastics, and other chemicals. These contaminants can have adverse effects on the health of animals and aquatic life, as well as on human health.

In some cases, industrial wastewater is treated before being discharged. However, the treatment methods may not be sufficient to remove all the contaminants, and under-treated effluents can still cause environmental pollution. Additionally, industrial activities can also contribute to water pollution through illegal discharges and spills of hazardous substances. For example, oil spills and leaks from factories and other land-based sources are a significant cause of marine water pollution, affecting both the ecosystem and marine life.

The impact of industrial waste on water pollution is significant. According to the most recent surveys from the U.S. Environmental Protection Agency, nearly half of the rivers and streams and more than one-third of the lakes in the United States are polluted and unfit for swimming, fishing, and drinking. Industrial waste discharges contribute a significant share of toxins to these water bodies. Furthermore, low-income communities are disproportionately at risk of the adverse effects of water pollution as they are often located closest to the most polluting industries.

To address the issue of water pollution caused by industrial waste, several measures can be taken. Firstly, strict environmental legislation and policies are necessary to regulate the discharge of industrial waste into water bodies. Secondly, the development and implementation of new technologies for industrial wastewater treatment and recycling can help reduce the amount of polluted wastewater discharged into the environment. Additionally, waste minimization practices and source reduction activities within industrial settings can also contribute to reducing industrial waste and its impact on water pollution.

Sewage and wastewater

The treatment and release of sewage and wastewater into water bodies is a regulated process, but it is not without its challenges. In certain circumstances, such as during heavy storms, water companies are permitted to release untreated sewage and wastewater into inland waters and the sea. These releases, known as storm overflow discharges, are meant to protect properties from overloaded sewers that could lead to flooding and sewage backup. However, this untreated sewage contains high levels of harmful pathogens, including viruses and bacteria, which can have detrimental effects on both human health and the environment.

The issue of sewage and wastewater pollution is prevalent in many parts of the world, including the United States and the United Kingdom. In the US, wastewater treatment facilities process a significant amount of wastewater daily, reducing pollutants such as pathogens, phosphorus, and nitrogen in sewage. However, it is estimated that these systems also release a substantial amount of untreated wastewater annually. Similarly, the UK's sewerage system has been criticized for its inadequacies, with water companies accused of profiting from pollution and failing to invest in protecting coastal and river environments.

The consequences of sewage and wastewater pollution are far-reaching. It poses risks to human health, with people contracting various illnesses, such as skin rashes, pinkeye, respiratory infections, and hepatitis, from sewage-laden waters. Additionally, it destroys ecosystems, kills wildlife, and impedes ocean recovery. The pollution also affects the economy, impacting sectors such as commercial fishing, recreational businesses, and tourism.

To address the issue of sewage and wastewater pollution, several measures can be implemented:

• Improve waste management practices: This includes proper treatment of industrial and agricultural waste to reduce the release of toxic chemicals and pollutants into water bodies.
• Upgrade sewerage infrastructure: Invest in modernizing and expanding sewerage systems to handle increased volumes of wastewater and reduce the frequency of overflow incidents.
• Strengthen regulations and enforcement: Governments and regulatory bodies should enforce stricter regulations on water companies and industries to ensure proper waste treatment and discharge practices.
• Promote public awareness and education: Educate the public about the impacts of sewage and wastewater pollution and provide guidance on responsible waste disposal and conservation practices.

Oil spills

Cleanup and recovery from an oil spill are challenging and can be very expensive. The process depends on several factors, including the type of oil spilled, the temperature of the water, and the types of shorelines and beaches involved. Spills may take weeks, months, or even years to clean up. Physical cleanups of oil spills, such as manually retrieving oil-soaked straw, are costly.

Agricultural processes

Agriculture is a major cause of water pollution, accounting for 70% of water withdrawals worldwide. Farms discharge large quantities of agrochemicals, organic matter, drug residues, sediments, and saline drainage into bodies of water. This includes the use of pesticides, fertilizers, and animal manure, which can enter groundwater depending on local land use and geologic conditions.

Agricultural runoff is the leading cause of water quality impacts to rivers and streams, the third leading source for lakes, and the second-largest source of impairments to wetlands. About half a million tons of pesticides, 12 million tons of nitrogen, and 4 million tons of phosphorus fertilizer are applied annually to crops in the continental United States. Increased levels of nitrogen and phosphorus from fertilizer and manure can stimulate algal blooms in lakes and rivers, leading to the development of hypoxic (low oxygen) conditions that are harmful to aquatic life. Algal blooms can also block sunlight, disrupting the ecosystem below the water surface that relies on the sun for energy. For example, nutrient runoff has decimated fish and shellfish populations in the Chesapeake Bay. Each summer, high levels of manure and fertilizer from the Mississippi River make their way into the Gulf of Mexico, causing a recurring "dead zone" thousands of miles wide.

Soil erosion, nutrient loss, and the runoff of pesticides and other contaminants from agricultural land are also leading causes of water quality impairment. Rainfall and snowmelt can transport these pollutants to surface waters, while other factors such as cattle loafing in stream corridors and stream channel erosion can also contribute to water pollution.

In recent years, persistent algal blooms, like red tides that produce toxins, have devastated coastal communities in Florida, staying long past their typical seasons and killing marine life en masse. Pollution via runoff, also known as agricultural nonpoint source pollution, is the leading source of harm to water quality for surveyed rivers and streams, the third-largest for lakes, and the second-largest for wetlands. It is estimated that 80% of marine pollution comes from land-based sources.

In addition to the direct impacts of agricultural runoff, there are also indirect effects on water quality. For example, the use of antibiotics, fungicides, and anti-fouling agents in aquaculture can contribute to polluting downstream ecosystems. The accumulation of nutrients in lakes and coastal waters can lead to eutrophication, impacting biodiversity and fisheries. High levels of nitrates in water can cause "blue baby syndrome," a potentially fatal illness in infants.

Agricultural pollution also extends to veterinary medicines (antibiotics, vaccines, and growth promoters), which can move from farms through water to ecosystems and drinking water sources. In CAFOs (Concentrated Animal Feeding Operations), excessive amounts of heavy metals like copper and zinc are fed to pigs and chickens to promote growth and prevent disease. These metals accumulate in the soil when animal waste is sprayed on farm fields and can contaminate water supplies. Copper toxicity can cause gastrointestinal and liver disorders, as well as other health problems in humans. Zinc pollution can also cause fish kills and damage to algae, crustaceans, and salmon.

Meat diets produce 59% more greenhouse gases than vegetarian ones, and beef production is 34 times more damaging to the climate than legumes like beans and lentils. Shifting land use to raise livestock delivers a one-two punch to the environment, releasing stored carbon into the atmosphere and destroying diverse ecosystems.

Microplastics

There are two types of microplastics: primary and secondary. Primary microplastics are tiny particles and microfibers that are shed from commercial products such as cosmetics, clothing, and other textiles, as well as fishing nets. Secondary microplastics result from the breakdown of larger plastic items, such as water bottles, due to exposure to environmental factors like the sun's radiation and ocean waves. Secondary microplastics make up the majority of microplastics.

To address the issue of microplastics in water, individuals can play a key role by reducing their use of single-use plastics and favouring products made with bio-based and biodegradable materials. Recycling and reusing plastic products are also effective remedies. Standard water treatment facilities cannot remove all traces of microplastics, so it is crucial to minimise their presence in the environment.

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